For Slate, Sean Rocha explains why there are so many different best-seller lists and how the data is collected.
The publishing industry may thrive on tell-all confessionals and novels named Disclosure, but when it comes to revealing how many books they actually sell, publishing houses are stonily silent. Whereas anyone can log onto imdb.com and find out exactly how much money a film took in at the box office, book publishers operate in a statistical haze. Even authors themselves, in most cases, cannot get access to hard data; instead, their publishers give them an approximate sales range, and they have to trust they’re not being cheated out of royalties.
The reason for all this secrecy is itself the worst-kept secret in the literary world: Hardly anyone buys books. Hyping a book as a “national best seller” creates an illusion of momentum and critical consensus that the phrase “over 25,000 copies sold”â€”which would actually be a pretty good figure for literary fiction sales in hardcoverâ€”does not. Thus, the industry’s modesty is protected by the fig leaf of relative sales: The current No. 1 on every fiction list is The Da Vinci Code by Dan Brown, but there’s no way to tell from the ranking whether it is selling 1,000 copies a week or 1 million.